Today’s Wonder of the Day was inspired by Lucas from Caledon . Lucas Wonders, “why do green sawfish have a body part that looks like a saw?” Thanks for WONDERing with us, Lucas!
Ahh…there's nothing like a relaxing day on the beach. As you soak up the Sun's rays, the waters of the Gulf of Mexico beckon to you. Could there be a better way to cool down than to go for a swim in the refreshing salt water?
Unbeknownst to you, though, a creature lurks nearby in those shallow, coastal waters. Three to four times the length of your average human being, this aquatic beast appears to be half-fish and half…chainsaw?
Is this the stuff of nightmares? Does this sound like the plot to a silly cable-television horror film? Such a creature couldn't be real…or could it? In fact, such creatures do exist. What are we talking about? Sawfish, of course!
There are two species of sawfish found in the shallow, coastal waters of the Gulf of Mexico and even in freshwater rivers in the southern United States: the smalltooth sawfish (Pristis pectinate) and the largetooth sawfish (Pristis perotteti). Both species are closely related to sharks. There are also five other species found in other oceans around the world.
Sawfish can grow to be quite large. An average smalltooth sawfish grows to 18 feet (5.5 meters) in length, while larger individuals may grow as long as 25 feet (or about 7.5 meters). Unfortunately, the smalltooth sawfish is an endangered species. Experts believe habitat loss, overharvesting, and entanglement in fishing nets are the primary causes for the declining sawfish population.
Do sawfish pose a danger to swimmers? Not likely! Sawfish aren't known to attack humans, and they tend to stay away from areas where humans would swim, such as near beaches.
So what do they do with their fearsome saws? Are sawfish the lumberjacks of the sea? Not quite! Sawfish eat other fish and crustaceans. They use their saws to catch and kill their prey.
For years, many scientists believed sawfish primarily used their saws to dig through sediment on the sea floor to find crustaceans and small fish to eat. Recent research, however, has shown that the sawfish rostrum is a much more complex tool than just a simple shovel.
Scientists have learned that the sawfish rostrum contains thousands of tiny sensors (known as ampullary pores) that can detect the invisible electric fields that surround living organisms. Using these special sensors on their saws, sawfish can locate fish swimming in the waters around them. Once located, a quick back-and-forth swipe of their saw can also cut their food in half, making it easier to eat!